Database that can access raw partitions/devices?
 

Is there an open source database that can directly make use of raw partitions or devices to store data, rather than files in a filesystem? I'm looking at setting up a database that will be particularly large (planning to give it at least 16TB to be sure it has room for growth over the next year or so).

I'd like to avoid using files as the data basis to avoid the extra layer of location mapping, as well as allowing the database engine (if it can ... it should if it can do this) to optimize data location itself for minimized seeking time.

raw on Linux was at one time going to be removed in favor of O_DIRECT but hasn't quite gone away yet because some things don't support O_DIRECT.

However, most things don't use raw. On doing some quick searches on both MySQL and Postgresql the two main open source DBs it seems that there isn't really raw space support for the latter. (FYI: MariaDB is a drop in replacement for MySQL for folks that don't want Oracle's ...um... stewardship of MySQL.)

Note that ext4 (filesystem) takes one way beyond the 16 TB limit of ext3.

One could look at btrfs but on a quick search I saw mention that it isn't really ready for MySQL so likely isn't for Postgres either.

By "raw" I mean just access to the partitions or devices w/o going through a filesystem ... not the BSD notion of raw. Sad that neither of these can do it.